This invention relates to graphics display systems in which the executable computer code for generating graphics information is embedded in the system hardware. More particularly, this invention relates to a method and apparatus for updating or otherwise reconfiguring graphics information displayed by the system without rewriting the embedded executable code.
Instrumentation such as avionic displays, industrial control displays and other video displays typically have static data such as lines, labels and numbers displayed on a screen. This data is known as a graphic "page" on which dynamic graphic data from external systems such as cameras and various aircraft sensors are displayed. A display application comprises a number of pages for interpreting different types of dynamic data. For example, in military aircraft, a pilot may choose among multiple pages for displaying the relative position of the aircraft, status of a weapon or a view of a target.
It is often desirable to change the nature of the graphic pages that appear on a display after the executable computer code is already embedded in the system hardware. This may occur, for example, if there is a change to the text and labels associated with a page. In a conventional embedded display system, such a change requires rewriting the executable code, recompiling it and substituting it for the existing executable code in the display system. Because the change affects the executable nature of the code, however, the code must be requalified by the appropriate authorities. This can be a time-consuming process.
Aside from the requalifying problem, the conventional approach of changing the executable code can be an enormous task where multiple hardware environments are involved. In an aircraft cockpit, for example, there are multiple graphic display systems of different hardware types such as raster scan, LCD or vector. For each type of display system, each update to a graphic page requires writing executable code unique to each system's associated data processor and then substituting the new code for the old, embedded code.
The present invention over comes these drawbacks of prior graphic display systems by permitting the static graphics information on a display to be changed as much and as often as desired without having to change previously embedded executable code. The invention also permits a change in graphics information to be made only once for all hardware systems, regardless of their different designs.